diff --git a/CodeWalker.Core/GameFiles/Resources/ResourceBuilder.cs b/CodeWalker.Core/GameFiles/Resources/ResourceBuilder.cs
index 773c9ec..a6ba380 100644
--- a/CodeWalker.Core/GameFiles/Resources/ResourceBuilder.cs
+++ b/CodeWalker.Core/GameFiles/Resources/ResourceBuilder.cs
@@ -139,7 +139,7 @@ namespace CodeWalker.GameFiles
             }
         }
 
-        public static void AssignPositions(IList<IResourceBlock> blocks, uint basePosition, out RpfResourcePageFlags pageFlags)
+        public static void AssignPositions(IList<IResourceBlock> blocks, uint basePosition, out RpfResourcePageFlags pageFlags, uint maxPageCount)
         {
             if ((blocks.Count > 0) && (blocks[0] is Meta))
             {
@@ -256,7 +256,7 @@ namespace CodeWalker.GameFiles
 
                 pageFlags = new RpfResourcePageFlags(pageCounts, baseShift);
 
-                if ((pageCount == pageFlags.Count) && (pageFlags.Size >= currentPosition)) //make sure page counts fit in the flags value
+                if ((pageCount == pageFlags.Count) && (pageFlags.Size >= currentPosition) && (pageCount <= maxPageCount)) //make sure page counts fit in the flags value
                 {
                     break;
                 }
@@ -338,10 +338,10 @@ namespace CodeWalker.GameFiles
             GetBlocks(fileBase, out systemBlocks, out graphicBlocks);
             
             RpfResourcePageFlags systemPageFlags;
-            AssignPositions(systemBlocks, 0x50000000, out systemPageFlags);
+            AssignPositions(systemBlocks, 0x50000000, out systemPageFlags, 128);
             
             RpfResourcePageFlags graphicsPageFlags;
-            AssignPositions(graphicBlocks, 0x60000000, out graphicsPageFlags);
+            AssignPositions(graphicBlocks, 0x60000000, out graphicsPageFlags, 128 - systemPageFlags.Count);
 
 
             fileBase.FilePagesInfo.SystemPagesCount = (byte)systemPageFlags.Count;
diff --git a/CodeWalker.Core/GameFiles/Resources/ResourceFile.cs b/CodeWalker.Core/GameFiles/Resources/ResourceFile.cs
index 65d9b2d..6d9ff99 100644
--- a/CodeWalker.Core/GameFiles/Resources/ResourceFile.cs
+++ b/CodeWalker.Core/GameFiles/Resources/ResourceFile.cs
@@ -96,17 +96,16 @@ namespace CodeWalker.GameFiles
     {
         public override long BlockLength
         {
-            get { return 20 + (256 * 16); }
+            get { return 16 + (8 * (SystemPagesCount + GraphicsPagesCount)); }
         }
 
         // structure data
         public uint Unknown_0h { get; set; }
         public uint Unknown_4h { get; set; }
-        public byte SystemPagesCount { get; set; }
+        public byte SystemPagesCount { get; set; } = 128;//default sizing to ensure there is enough space allocated when writing files
         public byte GraphicsPagesCount { get; set; }
         public ushort Unknown_Ah { get; set; }
         public uint Unknown_Ch { get; set; }
-        public uint Unknown_10h { get; set; }
 
         /// <summary>
         /// Reads the data-block from a stream.
@@ -120,7 +119,7 @@ namespace CodeWalker.GameFiles
             this.GraphicsPagesCount = reader.ReadByte();
             this.Unknown_Ah = reader.ReadUInt16();
             this.Unknown_Ch = reader.ReadUInt32();
-            this.Unknown_10h = reader.ReadUInt32();
+            reader.Position += 8 * (SystemPagesCount + GraphicsPagesCount);
         }
 
         /// <summary>
@@ -135,9 +134,8 @@ namespace CodeWalker.GameFiles
             writer.Write(this.GraphicsPagesCount);
             writer.Write(this.Unknown_Ah);
             writer.Write(this.Unknown_Ch);
-            writer.Write(this.Unknown_10h);
 
-            var pad = 256 * 16;
+            var pad = 8 * (SystemPagesCount + GraphicsPagesCount);
             writer.Write(new byte[pad]);
         }